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  1. #1

    Unhappy 2008 RXP-X RPM loss

    Good day all.

    Yesterday I went up to the lake to have some fun, but something just didn't feel right on either of the 2 2008 RXP-X's. When we gun it, it would shoot up to about 5800-6000 RPM until we got a bit of speed, then gradually run up and cap at 7200. The top speed of the ski is normal, but it just takes way longer to get there than usual. I never really paid much attention, but I though I remembered ~8000ish RPM as well.

    *Both skis have 35 hrs on them.
    *Last day riding prior to yesterday's 15 min of fame was up at Lake Tahoe on a fairly rough day (maybe a little more than fairly rough )
    *It may be my brain playing tricks on me, but I though I may have noticed them gradually loosing a little pep in the last few days, but I convinced myself it was just me getting use to the raw power.

    Does it sound like the infamous plastic super charger rings are just coming to haunt me, or something more serious? I've been doing a little research on doing the supercharger rebuild w/ metal rings anyway, so this may be a good time to do it.

    Thanks!


  2. #2
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    plastic charger rings? hahaha there not plastic, nor are they ceramic in the 08's. tahoe gets pretty nasty, were you hammer down hard through the chop? if so that kinda riding is hard on the chargers, have you ever checked the slip on them?!

  3. #3
    lol, glad they're not plastic.

    Ya, Tahoe chop can be pretty brutal. I went to a company picnic and the wind picked up in the afternoon (something new for Tahoe...), so we had some pretty brutal waves going back. I was able to keep 30-35 mph without getting chucked off; however, before pulling out we decided to have some fun with the chop. During that time we were riding them pretty hard, so I would imagine they were out of the water quit a bit. I'll be calling the See Doo shop where we bought them today, as they were closed yesterday.

    One other thought that came to mind was we bought gas up there that day. I realized after we paid that I forgot to ask for premium, so I would assume 87 or 89 went it. Would the lower grade gas cause a bit of an RPM loss?

    Regarding the slip on the charger, we haven't had them in the shop after the first 15 hours or so, except for winterizing/summerizing. Although, like I said, they only have 35 hours on them. We do ride them very hard. We're WOT or close to it 90% of the time, and do a lot of turning and accelerating. Not a lot of wake jumping, but don't pass up the opportunity

  4. #4
    I just got off the phone with the service dep't and he recommended checking the wear rings. Other than that, he said it may have something to do with the supercharger. How's that sound to y'all?

  5. #5
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    if you got a tank of crappy gas that would absolutely account for your lack of rpm's (knock sensor pulls all the timing out of it and it wont rev for diddley..... ask how i know) sounds like you beat the snot out of them, no problem with that, just gotta get up on your maintenance!! sounds like slip check is a must, if its not something else real obvious like a mangled wear ring or hose popped off

  6. #6
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    Just curious, but is Tahoe where you normally ride?? The elevation is around 6200 feet, and a "little rough" on Tahoe, is four to six foot waves!!!

    You should be fine with low octane fuel, considering the air density, or lack thereof.
    Just did a quick density altitude calculation for today, at 81 degree's, and the air density was 9000 feet!!!! So, around 7200 rpm is all your going to get, and the boat will feel way down on power.

    Stick a flashlight into your intake grate, turn off the garage lights, and look through your pump to see how worn your wear ring is. You shouldn't see hardly any light shining through.
    If you need to replace it, there is a section somewhere here, in the how to section(search function is your friend), and the last time I bought one, there were around $30 or so.

  7. #7
    No, I don't normally go to Tahoe - it gets too rough for me. I prefer Stampede, which is one of the reservoirs north of Tahoe. Although, it's altitude isn't much less than Tahoe.

    As a flight instructor, I'm very familiar with the density altitudes in the area It's not uncommon to have 8000-8500 ft density altitude in the valley at 5000 ft, so up at 6K it doesn't take much. That said, I've ridden on lots of hot days at Stampede, so I'm use to how they perform. It was one of the hotter days of the season on Sunday, though. Maybe the combination of a tank of 87, full fuel and a hot afternoon could explain the what we were feeling.

    I'll definitely check the wear rings before planning to go again, but what do you think about going and burning up a tank of gas some morning to see if a cooler temp helps? Or would it be better to just make an appt with the sea doo doctor?

  8. #8
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    It wouldn't hurt. That's why they have that density altitude thingie at the end of the runway there.....to many airplanes were "landing" in the lake, or on the Golf Course.
    Check your wear ring, and impeller. But I think it was just a combination of the weather, and maybe the 87 octane. Was it California, or Nevada gas??? There may be a difference in their "summer" blends, I'm not sure.

    I'm not sure what you want the dealer to do, or check, that you can't check yourself. Your supercharger washers are fine. At 100 hours on mine, I still had plenty of slip left, but had it rebuilt anyways.
    Now I have 160+ hours on the boat, and it still runs the exact same rpm and speed it did, when it had 10 hours on it. So they "age" well, if you do proper maintenance on them.
    And I don't necessarily ride slow. I'm known to run from Havasu to Topock, at full throttle. I think it's around 20 miles, but I forget. My dealer checks my Buds unit and says most of my riding time is at 7000 rpm and above. Not sure how far back it goes, but I'm usually either idling, or WOT. I don't need to sight see....I live here, I know what it looks like....I wanna go fast

  9. #9
    I got the gas in Zephyr Cove, so it was NV gas; however, do they do anything different to gas intended for marine? I live in NV, so I always use NV gas - but it's gas station gas.

  10. #10
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    No, marina gas is the same as regular gas.

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